Hydraulic pump or motor



April 10, l945. H. l.. cHlsHoLM, JR

' HYDRAULIC PUMP 0R MOTOR 4 Sheets-Sheet l Filed May 8', 1942 I Hee/ey A. 3f/snol, de.

April 10,1945u H.-|.. CHISHOLM, JR

HYDRAULIC PUMP 0R' MOTOR .Filed May '8, l1942 4 sheets-sheet 2 www nsf-Em zr" v Hneer 7 L. @ws/voz, de.

APril l0, 1945- H. L. cHlsHoLM, JR 2,373,457

HYDRAULIC PUMP OR MOTOR Filed May 8, 1942 4 sheds-sheet s v rm #Meer L CMM/0L, de.

pril 10, 1945. H. cHlsHoLM, JR y 2,373,457

HYDRAULIC PUMP OR MOTOR Patented pr. i, i45

Harry E.. lhisholm, ltr., BualmN. Y., assicr to Houdaille-Hershey Corporation, Detroit, Mich., a corporation of Michigan Application May 8, i942, Serial No 4425.46 3 Claims. (Gl. 10S-123) My invention relates to hydraulic devices, particularly of the rotary type, which can be operated with equal elciency to function as la pump or as a motor. My invention is particularly applicable to hydraulic structuressuch as disclosed in my copending application United States Serial No. 437,334, iiled April 2, 1942. The hydraulic structure in this pending application is operable either as a rotary pump or as a rotary hydraulic motor, ybut only with one direction ofvrotation of the rotor element, so that the structure is not reversible.

An important object of my present invention is to adapt structures of the type referred to for reversibility when operated either as a hydraulic pump or as a motor.

A further object is to provide improved construction and control of the rotor engaging blades for adapting the structure for equally eiiicient forward or reverse operation.

A further object is to provide simple valving means for controlling the direction of fluid ow through the rotor for either forward or reverse operation.

Another object is to provide means controlled by the valving structure for subjecting the rotor engaging blades to differential pressure cooperable with spring means engaging the blades so that the pressure engagement of the blades with the rotors will be substantially constant under all pressures of the fluid ilow through the structure and with minimum friction so as to avoid loss of energy and efliciency particularly during starting of the structure as a pump or as a motor.

The various features of my invention are embodied in the structure shown on the accompanying drawings, in ywhich drawings:

Figure 1 is a plan viewof the hydraulic structure;

Figure 2 is'v a section on plane II--II of Figure 3;

Figure 3 is a section on plane III-III of Figure 2;

Figure 4 is a section on plane IV-IV of Figure 2;

Figure 5 is an enlarged sectional view of one.

of the, blade structures shown'on Figure i3;

Figure 6 is a section on plane VI-VI of Figure 5 showing the blade in its upper position;` and Figure 7 is an enlarged transverse section of the iiuid flow controlling valve.

The structure shown comprises the cylindrical housing wall I0 having the inner wall `or head` ll integral therewith. On the other end of the housing a head I2 is provided whose flange i2 fits into the housing end and between which and the head Il are clamped the various elements which form the pump cylinder, the clamping being effected by a ring I 3 threading into the end of the wall I0. A shaft I4 extends into the housing and is journalled in ball bearings I5 and I6 supported respectively by the head ll and the head I2, the shaft extending outwardly from the head I'I' for mounting, or connection with, a driving source, such, as an electric motor, when the structure is used as a pump, or with devices to be driven when the structure is operated as a motor. vA fitting I'I receives the shaft and is 'secured as by bolts I8 to the head II and may serve as a bracket for supporting the hydraulic structure. The -tting I1 engages a washer I9 for compressing packing 29 around the shaft to prevent leakage.

` The pump cylinder forming elements comprise two rings 23 and 24, an inner plate 25, an, intermediate plate 26, and an outer plate 21, the outer-` diameters of the rings and plates being such that they will t snugly in the cylindrical bore'of the wall I0 to be clamped between the heads II and I2 by. the clamping ring I3. The rings and plates denne annular cylindrical spaces 28 and 29 into whichl the rotor elements 30 and 3| extend for rotation by the shaft IB to which they are secured as by keys 32. The pump may have any number of rotors'and rings, two sets being shown.

The rotor elements 30 and 3l are of generally elliptical or oval shape so as to define with the cylinder space walls crescent-shaped working chambers. The rotors are displaced on the shaft I4 so that the opposite working chambers 33 and 34 between the rotor 30 and the ring 23 'will have their maximum volumetric displacement when the working chambers 35 and 36 between the rotor 3I and the ring 24 have their minimum volumetric displacement.

For the cylinder spaces 28 and 29, in which the rotors operate, diametrically opposite fluid inlet passageways s and s' and diametrically opposite uid discharge passageways d' andd' are provided. To form these passageways, the rings 23 and 24 have transversebores 4I therethrough which alignwith the bores 62 in the plates 26 and 21. The inlet passageways s and s'l communicate with the cylinder spaces through ports 39 and 39', while the passageways d and d' communicate with the cylinder spaces through ports 40 and 40' (Figure 2). Attheir inner ends the inlet and outlet passageways are closed by the plate 25.

The rings 23 and 24 are each provided with diametrically opposite blades 43 and 43' for cooperating With the rotors surrounded by the rings, the blades operating in radially extending slots or chambers 44 and 44' respectively, the blades 43 being located between the inlet passageway s and the outlet passageway d, while the blades 43 are located between the inlet passageway s' and the outlet passageway d. Engaging the outer end of each blade is a plunger or piston 45 slidable in a passageway 46 extending radially through the corresponding rings 23 and 24. The plunger is cylindrical and bored to receive a spring 41 which extends outwardly into a plug 48 secured to the housing wall Hl. The pressure of the springs 41 tends to keep the blades seated with their inner ends against the respective rotors.

The head I2 of the hydraulic structure has the cylinder bore 4S therethrough forming a valve chamber for a valve o. This valve has a central passageway therethrough for the end of the valve stem 50 to which it is secured, this stem extending ouwwardly beyond the outer end of the head I2 and terminating in a grip 5I, a packing box 52 preventing leakage. Other passageways 53 extending longitudinally through the` valve provide for flow of uid from one end of the valve chamber to the other. The valve has the annular port 54 which, when the valve is in its inner position shown in Figure 3, spans the inner annular port 55 and the intermediate annular port 56 formed in the head I2, and when the valve is in its outer the inlet 58 will now flow through the valve paswhich delivers fluid under pressure.

position as shown in Figure 4, the valve port spans the intermediate port 56 and the outer annular port 51 in the head l2. As shown on Figures 1 and 3, the iiow passageway 58 in the head I2 cornmunicates with the outer end of the valve chamber and a, ow passageway 59 through the head communicates with the valve chamber at a. point between the inner and outer ports 55 to 51 and in line with the intermediate port 56 in the head I2.

The inner port 55 in the head I2 is connected by a passageway 60 (Figure 3) with the outer end of the pump discharge passageway d, and similar passageway 6I (Figure 4) connects the port with the pump passageway d'. The outer port 51 in the head l2 is connected by a passageway 62 (Figure 4) with the pump inlet passageway s, and a similar passageway 63 (Figure 3) connects the port 51 with the pump inlet passageway s'.

When the structure is to be operated as a pump. the passagewaySB in the head I2 will be the inlet for uid to be drawn from a source of supply such as a reservoir, and the passageway 59 in the head I2 will be the discharge outlet for the pump. Referring to Figure 3, with the valve o in its inner position for spanning the head ports 55 and 56, the pump is rotated by the motor in counter-clockwise direction (Figure 2). The fluid Awill now be drawn in through the inlet 58 into 4the outer end of the valve chamber and into the sageways 53 to the head port 55 and from there through the passageways 60 and 6I into the pump passageways d and d', the fluid being discharged from the pump under pressure through the passageways 62 and E3 into the outer head port-51 and then through the valve port 54 and out of the outlet passageway 59.

If it is desired to operate the hydraulic structure as a motor, the passageway 59 in the head I2 is connected with a source, such as a pump, With the valve in its inner position shown in Figure 3, the iiuid under pressure will be directed by the valve port 54 to the inner head port 55 and fromr there through the passageways 60 and 6I to the pump passageways d and d for engagement with the rotors for clockwise rotation thereof` and of the shaft i4, thespent uid entering the pump passageways s and s for iiow through the passageways B2 and 63 to the outer head port 51 and from there through the passageway 58 back to the reservoir from which the pump receives its uid supply for producing the pressure ow for driving the hydraulic structurel as a motor.

If it is desired to drive the hydraulic strucport 54 to the outer head port 51 and from there through passageways 62 and 63 into the pump passageways s and s for engagement with the rotors for counter-clockwise rotation thereof, the spent fluid entering the pump passageways d and d' from where it iiows through the passageways 6I! and 6I to the inner head port 55 and then through the valve passageways 53 to the outer end of the valve chamber for return through the passageway 58 to the reservoir. Thus, by setting of the valve v, the hydraulic structure can be operated in either direction, either as a pump or as a motor.

In order to obtain eiciency, it is very important that the blades be held with their tips in perfect contact with the rotors so as to avoid leakage of iiuid directly from the high pressure to the low pressure side, but at the same time the pressure holding the blades against the rotors should be kept constant and with minimum friction be tween the blades and the rotors, whether the hydraulic structure is operating in either direction as a pump or as a motor. The blades are of flat rectangular shape and are disposed in a radial plane extending through the axis of the cylinder and rotor, and the contact end of each blade is of V cross section for presenting a contact edge to the rotors, the blade ends beipgrsymmetrical at each side of the centralvor contact edge with the slope of the surfaces 64 and 65 at the most efficient angle. As shown, the angle of slope is about 30. This contact edge is at all times the sole area of engagement of the blade with the rotor. During operation 0f the structure in either direction, either of the surfaces 64 or 65 will be subjected to the high pressure fluid while the. other surface is subjected to the low pressure. This high pressure against the blade ends will tend to shift them outwardly against the resistance o their springs 41, and this outward effort against the blades is always in direct proportion to the pressure of the fluid. I therefore provide means for subjecting the outer ends of the blades at all times to the same hydraulic aereas? pressure per square inch as that of the high pressure acting against either end surface of the blades. Such'counteracting pressure against the blades is preferably controlled to be at all times slightly greater than the outward pressure against the blades so that this dilerential pressure will assist the springs dl in holding the blades in proper contact with the rotor. From the description thus far it is noted that, while the hydraulic structure vis being operated in either direction as a pump or as a motor, the intermediate head port 56 is always subjected to the uid ilow under high pressure, and that, when thestructure is operated as a pump, the intermediate port t is in'connection with the high' pressure discharge of thepump, and that, whileA the structure is'being operatedas a motor the port 56 is always subjected to the high pressure fluid which operates the structure as a motor.

Referring particularly to Figures 3 to 6, inclusive, a channel 66 is cut in the housing wall l@ in alignment with the passages d6 in which the plungers i5 for the blades d3' operate, and a similar channel (Figure 2) is provided for the plungers for the blades d3. Channels 6l in the mechanism, may be readily reversed. The blade under spring action and dilerential' pressure in cooperation therewith will .at all times lmaintain. accurate contact of the blades with the rotors and with minimum friction so as to avoid loss.

of energy and efilciency particularly during startl .ment, construction and operation shown and deouter face of the plate il extend from the` chan Y nels et and are connected by passageways 68 and 59 in the head l2 with the intermediate head port 56, as shown in Figures 3 and 4.

The surfaces Sli and 65 at the contact endof each blade are of the same area, and this area is so proportioned to the area of the plunger ciently greater than the outward pressure against the blades so that this pressure differential may assist the spring il in holding the blade in proper contact with the rotor. This pressure dilferential varies in value in direct proportion with the variation in the pressure of the high pressure flow through the structure, thus automatically increasing the force of blade contact as demanded by the operation of the structure. The difierin the plate 26, and through passageways ,ll in V jthe plate these chambers communicate with channels l2 in the outer side of the plate 25, which channels lead to the inner space in the structure through which the shaft l@ extends, this space being at all times in comm 1nication with the low pressure outlet through the valve passages 53.

The movement of the of the valve v to its inner or outer positions is `limited by the engagement by the grip 5l with the end of the packing box 52, or by engagementofthe abutment pin'lS on the stem with the head wall at the outer end of the valve chamber, asshown in Figure 4, these two limits of movement of the stem accurately setting the valvein its inner position shown on Figure 3, or its outerposition shown on Figure 4.

I have thus produced a simple hydraulic struc` ture of the type referred to which can operate equally emciently as a pump or as a hydraulic motor and which, by manipulation of simple valve valvestem@ for setting d5 which is subjected to the counteractin'g high pressure that the counteractingA pressure is sufiiscribed, as changesand modifications may be made without departing from the scope of the invention.

I claim as my invention:

1. A hydraulic rotary structure of the type described vcomprising a housing dening a cylinder space, a rotor of elliptic cross section within said space connected to cooperate with vthe cylinder space Walls to dei'lne a working chamber, inlet and outlet ports4 for said working cham. ber, a flat rectangular blade between said ports disposed in a radial plane extending throughthe axis of said cylinder spacc/ndwrgtgna chamber/Y, Y' Yin'said lus'igforsaid blade, spring means urging said blade into contact with said rotor, a valve chamber in said housing, a fluid inlet and a iluid outlet for said valve chamber, passageways connecting said valve chamber withl the ports for said working chamber, a valve in said valve chamber adapted for setting to control the direction of the fluid ow from said valve chamber through said ports and working chamber, said blade at its contact end being of V-shape cross section to provide a contact edge engaging said rotor surface and sloping surfaces at opposite sides of said edge of the same area, said contact edge alone being at all times the sole area of engagement of the blade with the rotor, one of said surfaces being exposed to the high pressure of the fluid ilow during operation ofthe structure tending to shift the blade longitudinally outwardly against the force of said spring means,v

a piston abutting said blade but otherwise disconnected thererom, a high pressure flow pas-A sageway between said valve chamber'and said piston and means whereby setting of said valve for either direction of operation of said structure will connect said high pressure now passageway to the piston for flow of high pressure fluid against the piston for counteracting the outward pressure on said blade, the area'of the piston exposed to the fluid pressure being -only slightly greater than the varea of the surface at the contact end of the blade exposed to the high pressure whereby a slight differential pressure on the blade will assist said spring means in holding the blade in contact with the rotor;

2. A hydraulic rotary structure of the type described comprising a housing defining a cylinder space, a rotor of elliptical cross section within said space to cooperate with the cylinder space wall to define a working chamber, inlet and outlet ports for said Working chamber, valve means adapted to be set to control the direction of. fluid ow through said structure for operation thereof in either direction as a motor or as a pump, a flat rectangular abutment blade for the rotor operable in a radial plane' extending through the axis of said cylinder space and rotor, a guide slot for said blade and a wall closing the outer end of said slot, the'contact end of said blade being of -V-shaped cross-'section to define a contact edge and opposite sloping surfaces of 'equal area, said. contact edge alone being at al1 times the sole area of engagement of said blade with said rotor, one of said surfaces being subjected during operation of the structure to the high pressure fluid flow therethrough tending to shift the blade longitudinally away from the rotor, said slot closure wall having a bore therethrough and a cup-shaped piston movable in said bore for abutting engagement with the outer end of said blade, a. spring extending into said piston tending to urge said piston against said blade to hold the blade with its contact edge against the rotor, and a passageway in said housing open during either setting of said valve means for conducting high pressure iiuid ow against said piston whereby said piston will assist said spring in holding the blade in contact with the rotor, the area of the piston subjected to said pressure being only slightly greater than the area of the surface of the contact end ofthe blade subjected to the high pressure ow whereby only a slight differential fluid pressure of the blade will assist the spring in holding the blade in contact with the rotor with minimum friction engagement,

3. A hydraulic rotary structure of the type described comprising a housing defining a cylinder space, a rotor of elliptical cross section within said space to cooperate with the cylinder space wall to define a working chamber, inlet and outlet ports for said chamber, valve means adapted to be set to control the direction of fluid flow through said structure for operation thereof in either direction as a motor or as a pump, a flat rectangular blade disposed in a radial plane extending through the axis of said cylinder space.

and rotor, the contact end of said blade being of V-shape cross section to define a contact edge engaging said rotor and opposite sloping surfaces of equal area, said contact edge alone being at all times the sole area of engagement of said blade with said rotor, one of said surfaces being subjected during operation of the structure to the high pressure fluid flow therethrough tending to shift the blade longitudinally away from the rotor, a guide slot for said blade and a Wall in the upper end of said slot, a bore through said wall, a cupshaped piston movable in said bore for abutting engagement with the outer end of said blade but otherwise disconnected from said blade whereby said blade may freely operate in said slot without interference by said piston, a spring extending into said piston for holding the piston abutted against the blade for engagement of the contact edge of the blade with the rotor, and a passageway in said housing open during either setting of said valve means foi conducting high pressure fluid flow against said piston for movement of said piston to assist said spring in holding the blade in contact'with the rotor, the area of the piston subjected to said fluid pressure being so proportioned to the area of the surface of the contact end of the blade subjected to the high pressure whereby only a slight differential fluid pressure on'the blade will assist the spring in holding the :blade in contact with the rotor with minimum friction Ibetween the blade and rotor when the rotor is operating.

HARRY L. CHISHOLM, JR. 

